A\C is always on
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E240 -2003 E55 AMG -2005
A\C is always on
Question my mechanic tells me the Air Con compressor in our cars still runs even if you turn it off on the climate controls. So effectively the compressor is running constantly is this true and if so why have the option to turn it off i the first instance? 
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Cryptic as always Plutoe. I believe most a/c compressors have a clutch. So the belt to the compressor is running all the time, but the compressor only engages when the clutch is engaged. If the a/c clutch is engaged all the time, then your compressor is running all the time. If not, then the compressor isn't really running all the time.
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Car free at the moment
The w211 a/c compressor does not have a clutch. The compressor itself runs all the time. However, it is a variable displacement compressor. It can operate at (IIRC) a range of 2% to 100% of rated capacity. So when you turn the a/c "off", you don't disengage the compressor as on most cars, but instead it shifts to the 2% capacity. It's still turning, but doing essentially no work.
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From: dmv
2009 E550 2000 Honda civic mash n' go
The w211 a/c compressor does not have a clutch. The compressor itself runs all the time. However, it is a variable displacement compressor. It can operate at (IIRC) a range of 2% to 100% of rated capacity. So when you turn the a/c "off", you don't disengage the compressor as on most cars, but instead it shifts to the 2% capacity. It's still turning, but doing essentially no work.
Thread Starter
Member
Joined: Feb 2015
Posts: 179
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E240 -2003 E55 AMG -2005
The w211 a/c compressor does not have a clutch. The compressor itself runs all the time. However, it is a variable displacement compressor. It can operate at (IIRC) a range of 2% to 100% of rated capacity. So when you turn the a/c "off", you don't disengage the compressor as on most cars, but instead it shifts to the 2% capacity. It's still turning, but doing essentially no work.
Thread Starter
Member
Joined: Feb 2015
Posts: 179
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E240 -2003 E55 AMG -2005
Part of the compressor is running when the car is on----with regards to your next question----"So effectively the compressor is running constantly is this true and if so why have the option to turn it off i the first instance?
"
That question does not warrant a response other that say, please take an hour of your time and goggle MB AC compressor functions--after that you will no doubt delete your post!!
"That question does not warrant a response other that say, please take an hour of your time and goggle MB AC compressor functions--after that you will no doubt delete your post!!
